Speakers

Metalloenzymes and metallocofactors in nature often demonstrate uniquely high efficiency that cannot be observed elsewhere. One example is C-H bond activation by non-heme iron enzymes; mononuclear and binuclear iron sites can utilize O2 to form high-valent intermediates that abstract H atom from strong bonds such as the C-H bond of methane. The principle of these reactions has been elucidated on the basis of intermediate structures established by nuclear resonance vibrational spectroscopy, revealing that spin-polarized charge transfer from oxo ligand to Fe center determines intrinsic barrier for the reaction.

A series of high-valent organometallic complexes that show different rates of reductive elimination process have been spectroscopically and computationally studied. A good correlation amongst the energy level of redox-active metal d orbitals, the type of supporting ligands, and cross coupling reaction rate demonstrate that the activity and selectivity of C-C bond cross coupling reaction can be understood in parallel with enzyme’s strategy to raise the reduction potential of a metal center by dissociating or exchanging ligands.